AstronomyUkraine Posted June 12, 2021 Share Posted June 12, 2021 After reading a few articles by members on here regarding widefield imaging, a germ of an idea popped into my head. I have at my disposal several Canon EOS L series lenses that I use for wildlife imaging. As anyone who has been into photography for any length of time knows, the L series lenses are high quality. The one I want to use is my 100 - 400 L IS USM. It is not extremely fast like the Samyang lens other members are using, but it is still a respectable f4.5, with a 77mm filter size. My plan is to buy a ZWO-EFW-EOS-II adapter which will allow me to connect my EFW to the Canon lens, autofocus won't be an option, but I can use a Bahtinov mask, and the focusing mechanism on the lens is very good, allowing fine adjustments. The only problem I can see is platesolving and finding the focus point, but this adapter is specially made for Canon cameras to operate with the EFW and the 1600 which I use. So hopefully the focusing shouldn't be a problem. The 100 - 400 lens also has a built in tripod mount, so bolting it down to a dovetail won't be a problem. If I have overlooked anything, or anyone has any experience using this type of lens for astro imaging, let me know your thoughts. Brian Quote Link to comment Share on other sites More sharing options...
MarkAR Posted June 13, 2021 Share Posted June 13, 2021 I have the same lens, finding focus isn't too bad. Last time I messed around at night with it I forgot to take off the UV protective filter. I think this might have caused astigmatic looking stars. Quote Link to comment Share on other sites More sharing options...
AstronomyUkraine Posted June 13, 2021 Author Share Posted June 13, 2021 10 hours ago, MarkAR said: I have the same lens, finding focus isn't too bad. Last time I messed around at night with it I forgot to take off the UV protective filter. I think this might have caused astigmatic looking stars. I have done that myself taking images of the moon. 😀 Quote Link to comment Share on other sites More sharing options...
Galileo Posted May 31, 2022 Share Posted May 31, 2022 I always used Canon lenses for some of my astrophotography and was happy with my results until I got an ASKAR ACL200 apo lens and realized that although Canon lenses are really good there are plentiful aberations that don't show up in normal photography. Quote Link to comment Share on other sites More sharing options...
paul Posted June 1, 2022 Share Posted June 1, 2022 On 6/12/2021 at 8:10 PM, AstronomyUkraine said: After reading a few articles by members on here regarding widefield imaging, a germ of an idea popped into my head. I have at my disposal several Canon EOS L series lenses that I use for wildlife imaging. As anyone who has been into photography for any length of time knows, the L series lenses are high quality. The one I want to use is my 100 - 400 L IS USM. It is not extremely fast like the Samyang lens other members are using, but it is still a respectable f4.5, with a 77mm filter size. My plan is to buy a ZWO-EFW-EOS-II adapter which will allow me to connect my EFW to the Canon lens, autofocus won't be an option, but I can use a Bahtinov mask, and the focusing mechanism on the lens is very good, allowing fine adjustments. The only problem I can see is platesolving and finding the focus point, but this adapter is specially made for Canon cameras to operate with the EFW and the 1600 which I use. So hopefully the focusing shouldn't be a problem. The 100 - 400 lens also has a built in tripod mount, so bolting it down to a dovetail won't be a problem. If I have overlooked anything, or anyone has any experience using this type of lens for astro imaging, let me know your thoughts. Brian Quote Link to comment Share on other sites More sharing options...
paul Posted June 1, 2022 Share Posted June 1, 2022 (edited) I have the same adapter but hooked up to the Samyang. I only got around to testing it in the last couple of weeks. First light was stupid because I left fitted the 10mm extension it comes with. Removing it at least allowed me to see trees in the distance, I had to add back a 0.5 mm spacer for it to focus on infinity. I haven't managed to take any images to check quality yet. (I have the stick-on dew-heater so I guess the total additional spacing is currently around 0.6mm). Edited June 1, 2022 by paul Quote Link to comment Share on other sites More sharing options...
paul Posted June 2, 2022 Share Posted June 2, 2022 Quote Link to comment Share on other sites More sharing options...
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